Remodeling Assistance

I am new to the forum and this is my first post. I am in the process of remodeling the master bath in my home which is on the second floor. I have attached the pic. of the old layout and the new layout (both floor plan and vanity plan). I would like to do as much of this as I can. I am trying to avoid any mistakes before it is too late. Basically I am adding a drop in corner whirlpool (MTI-26) and replacing the old shower/tub combo with a kerdi base walk in shower. As the Old layout pic shows there is currently a 1-1/4" drain which ties into the 4" drain for the toilet. My questions are:

1. Can I tie the drain for the new tub into the 1-1/4" as shown in the new layout.

2. What do I stub out of the sub-floor? (I not sure how to make the final connections to the drains for the tub and shower drain one the sub-floor is down.

3. Also if anyone sees any problems with the new layout please feel free to chime in.

I am currently at work and will take pictures of the current status of the project which will show the plumbing under the sub-floor.

Couple of general points...a tub requires a 1-1/2" drain, a shower a 2" drain. Each must be vented separately within a specific distance, depending on the size of the pipe. Traps for things like the shower and bathtub should be right underneath the drain. All drain lines must slope a minimum of 1/4"/foot, with no flat spots or uphill runs. You cannot go from a larger sized drain to a smaller one...you can only go from a smaller one to a larger one. The ultimate size of the drain will depend on the number of fixture units (i.e., drain capacity) it needs to drain, as well as dictate the size of the vent.

Thanks for the response Jadnashua even though it wasn't what I was hoping to hear. It difenately is never as easy as one originally thinks! Since the old drain is 1-1/4" I can only assume codes have changed since then (1965-1970's) requireing the sizes that you have outlined.

Is it absolutely necessary for them to have a seperate vent. The tub/shower didn't have a seperate vent and we never had any problems with it or the toliet. What is the benefit of having each one vented??

If I could get by with the existing vent could I replace the 1-1/4" going into the 4" tee with a 2" pipe (which would be for the shower). Then tie in the 1-1/2" pipe for the tub into the 2" drain. Would a 4" vent be enough for all of these drains.???

If I must put vents do they have to vent through the roof?? I have no access to an attic as the house orginally had a flat roof.

Each trap must be vented, but that doesn' mean individual vents through the roof...there are rules about combining them...basically 6" above the flood plane of the highest fixture. Most inspectors want to see that at 42" or more above the floor (kitchen counter 36" + 6"). A vent may not help draining, but it prevents the siphon of it draining from sucking the water out of adjacent traps. Once that happens, you have a direct, opening to your sewer system, and sewer gasses, bugs, etc., can get into the house...not nice.

1. the drain to the old tub is not vented and it is an "S" trap, both violations of EVERY plumbing code.
2. The toilet is between the tub and the toilet's vent, if there is one because none shows in your pictures. Again a violation of every plumbing code.
3. 1 1 4/" tub drains were NEVER allowed even back in the early 1900's when they were still using lead drain pipes.
4. We cannot be sure, using your pictures, whether your new piping will be installed any better than the old ones, especially if you use the old ones.
5. Contact a plumber, because your building department will not help you other than to reject it when you call for the inspection. Then they may tell you to call a plumber to have it installed correctly.

What we are trying to tell you is there are at best just a very few ways to do this right and many, many ways to do it wrong. There is no way even an expert plumber can possibly give you all of the information you need to do this right without actually being on site. If you insist on trying to DIY, you will almost certainly not pass code inspection. The sooner you get a plumber involved, the less it will cost you and the sooner your project will be completed.

I really appreciate all of the advice. The main reason I was driving to DIY is that plumbers in this area or in extreme demand. Looks like I will just wait till I can get in touch with one. I will post an update when I found out what is needed.

I had a plumber come out and look at what I wanted to do. He said there was two things he could do. One would be to run a 3" line to the tub and reduce down to a 2" for the tub drain. He said this would serve as a "wet" vent. Then the 1-1/2" drain would for the shower would tie into the 3" were it currently does now. He did say that it isn't code but assured it would work and said it is much easier than running a vent to the inside wall then up through the roof. He left it up to me for me to decide. What do you guys think??

Wet venting may not be allowed, but is in some codes...you'd have to check with the local inspector. While older showers may have used 1.5", while he's in there, it would be best to run 2"; then, it would both meet code and if you redid things, you'd be better able to use normal parts.

I had a few questions relating to putting the subfloor back down and preparing it for porcelain tile. I am familiar with John Bridge forums but figured since I have an account here it couldn't hurt to post my questions on this site. For replacing the area I cut out of the subfloor I planned on running 2x4 where the seams of the 3/4" plywood comes together. The tile store has told me that I don't need to put an additional layer of plywood on the current 3/4" plywood (I don't believe it is tongue and groove). They advised thin setting shutler's ditra on the subfloor then tiling over the ditra. Does this sound adequate?? Also I plan on tiling some portions of the wall and I was considering doing 1/2" plywood then sheet rock. They told me that just the sheetrock would be fine. Is this also enought support for the tile.

3/4" ply (no D-face!, C or better) is adequate for a subfloor. Keep in mind, the joists must be up to spec, too. Ditra over that would be fine. On the walls, 1/2" drywall is fine - no need for plywood behind it unless you anticipate people really pounding on it. Keep in mind that drywall paper facing has a grain to it and is stronger when installed horizontally verses vertically.

You need two different types of thinset to install the tile. What may be easier is to buy an unmodified and the addative. Mix it with the addative to attach the Ditra to the floor, then mix up the same stuff without the addative to set the tile. If you can find it, Ditraset thinset is a great unmodified thinset - nice and creamy, easy to work with. Mapai has a decent one - generally Lowes sells that. HD doesn't have a decent unmodified thinset - they generally carry Custom's price leader, which is not what you want. Their modified thinsets are fine, and they do make a decent unmodified, but HD doesn't carry it.

I appreciate your help jadnashua. What are you refering to when you say "no D-face, C or better"? I plan on looking for the deflection calculator on John's site I saw it once but coundn't find it the other day.

Back to the floor if there are small cracks ie. where the plywood comes together does that need to be filled with something wood filler or will the thinset do the job at filling these cracks.

Also for the tile shower I am planning on using the kerdi base. For the walls of the shower my tile supplier has advised me to use sheet rock for the walls then painting Hydro Ban from Laticrete directly on the sheet rock. I have been reading alot about the showers and I haven't heard of anyone using this method. Any suggestions??

For the shower I was planning on having it completely enclosed? Is this a bad idea or not??

Plywood construction is made up of graded plies...a D face is as bad as they get and can have voids in it. An A-face is the best it gets in construction ply. You dont' want any D-faces, so something like BCx, where x is for exterior glue, sometimes called exposure I. Often, the cheapest ply is CDx...that would not be suitable for use under tile because one face is D.

No need to fill the gaps in the ply between sheets, as long as you have the edges supported underneath or by T&G construction unless you are using something like self-leveling cement (slc) to level the floor; then, any gap will allow it to leak through.

Don't mix shower systems...If you are going to use Kerdi (a good system), use Kerdi for the whole thing. Latticrete makes a good product too, but if you go that route, use it for the whole thing as well...again, don't mix systems. And, drywall is the preferred, recommended wall surface when using Kerdi...the Kerdi membrane, correctly installed, will make it entirely waterproof with no chance of it getting wet.

Are there any issues with having the shower completely enclosed. I think the majority of showers I have seen have at least one wall not go completely to the ceiling. I could see where this allows the hot moist air to escape the shower. Is it necessary to leave one wall shy of the ceiling or if the shower is completely enclosed is there special venting that is needed?

If the shower is totally enclosed, it is likely to fill up like a steam shower. To make a steam shower is a TOTALLY different set of requirements - much more stringent than a traditional shower. I suggest you check out www.johnbridge.com. The Tile Council of North America has design guidelines on what is required to make a steam shower that should be followed. It is often much easier to leave an opening, but the whole thing still needs to be done properly.

Drying out the shower will be problematic if you don't either leave the door open, or have some way of venting it...continuous dampness tends to make for a nasty place - mold and mildew. It can easily start to rot out the structure if not done properly.

[One would be to run a 3" line to the tub and reduce down to a 2" for the tub drain. He said this would serve as a "wet" vent. Then the 1-1/2" drain would for the shower would tie into the 3" were it currently does now. He did say that it isn't code but assured it would work and said it is much easier than running a vent to the inside wall then up through the roof. He left it up to me for me to decide. What do you guys think

I think you need a different plumber. One who knows how to do it correctly, not try to get by with something, "as long as it is not going to be inspected". Which is the mantra of the do it yourselfer who is only interested it getting the work done and how it is done is immaterial.